Electric-bath m etal-h eati ng apparatus



(No Model.)

G. D. BURTON. ELEOTRIC BATH METAL HEATING APPARATUS.

Patented Apr. 9, 1895.

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UNITED STATES PATENT OFFICE.

GEORGE D. BURTON, OF BOSTON, MASSACHUSETTS.

ELECTRIC-BATH METAL-H EATING APPARATUS.

SPECIFICATION forming part of Letters Patent No. 537,006, dated April 9, 1895.

Application filed August 24, 1893. Renewed September 10, 1894. Serial No. 522,598 (No model.)

.To aZZ whom it may concern.-

Be it known that I, GEORGE DEXTER Boa TON, a citizen of the United States of America, residing at Boston, in the county of Sulfolk, in the State of Massachusetts, have invented certain new and useful Improvements in Elec-' trio-Bath Metal-Heating Apparatus, of .which the following is a specification.

This invention relates to the art of heating metal for forging or other metal working operations by immersing the metal or that portion thereof to be heated in a suitable bath and passing therethrough an electric current of such a character as to cause the formation of an electric arc at or below the surface of the solution and around the metal to be heated, whereby the heating thereof is quickly effected.

The object of the invention is to provide means for the automatic connection and disconnection of the bars to be heated with the electric current on the withdrawal and insertion of said bars.

The invention consists in the combination of a receptacle, a bath of proper resistance and conductivity disposed in said receptacle, means for connecting said bath with one electric pole, and an automatic clamp or clamps for grasping the bar to be heated and connecting it with the other electric pole.

Figure 1 of the accompanying drawings representsaperspective View of this electric bath metal heating apparatus. Fig. 2 represents a transverse section thereof.

The same reference-numbers indicate the same parts in both figures.

A receptacle 1O composed in whole orin part of wood, earthern ware or other insulating material, or it may be made of metal and act as one pole, and constructed in the form of a tank or other suitable vessel, contains a bath in which the metal to be heated is inserted and partially or wholly immersed. A plate 11 preferably of lead and preferably in the form of a lining for the tank or receptacle, serves as a conductor to connect the bath with one pole of a direct current generator or other suitable electric source, being provided with a binding post 12 or its equivalent.

An automatic clamp is disposed in proximity to the bath 20, being preferably mounted on the edge of the receptacle 10. This clamp is of any suitable construction and is connected with the other pole of the electric source. The clamp herein shown for this purpose comprises an eye 31 having an insulating base plate 32, which is set in a notch of the upper edge of said tank or receptacle. This eye is flared at its upper outer edge and lower inner edge to permit the bar to be adjusted at an incline for insertion in the solution.

A sliding pin 35 provided with a binding post 36 is movable in a hole in the upper side of the eye 31 and serves as a contact pin or movable jaw for conveying the current to the bar to be heated. The lower end of this pin may be rounded or pointed. A weight-37 is adjustable by means of a set screw 38 on said pin. By the adjustment of this weight the distance which the pin projects into the hole of the eye 31 can be regulated so as to suit bars of different thicknesses. A number of these clamps may be disposed along the edge of the tank or on a support outside the tank.

A conductor 40 connects the clamps 30 with one of the electric poles of the electric source and a conductor connects the bath 20 with the other electric pole.

The bath 20 consists of any suitable electrolyte which with the current used will cause the [formation of a voltaic arc surrounding the metal to be heated on the insertion thereof. Either an acid or an alkaline solution will answer the purpose. I have used a solution of sal-soda of a specific gravity of 1.305 at 84 Fahrenheit; also a solution of equal parts of sal-soda and cream of tartar of a specific gravity of 1.255 at 77 Fahrenheit; also a solution of hydrate of potassium of a specific gravity of 1.130 at 77 Fahrenheit; also a solution of pulverized caustic potassium of a specific gravity of 1.215 at 78 Fahrenheit, or a solution of caustic potassium of a specific gravity of 1.210 at 79 Fahrenheit. I deem these solutions preferable to an acid solution as the latter is apt to affect the temper of the metal.

The strength of the solution and the character and proportion of the ingredients may be varied without departing from the scope of this invention.

The nominal current used for ordinary small work is from forty-five to sixty volts and forty to eighty amperes, according to the size of the piece and the bath.

The voltage of the current employed may vary from forty-five volts upward and the amperage from forty amperes upward, according to the size of the pieces to be heated. The bars call for what current is required to heat them. They are held as near the surface as practicable, being submerged sufficiently to cover the parts to be heated and to cause the formation of the hydrogen jacket and the voltaic arc.

In the use of this apparatus, the bar to be heated is thrust through one of the automatic clamps 30, the pin 35 being lifted by the bar as it is thrust into the eye, said pin maintaining contact with the bar, and serving to conduct the current therefrom. When the bar is inserted in the bath an electric arc is formed, which surrounds or forms an envelope around the bar or that portion thereof which is immersed. The are serves to heat the bar in a few seconds or minutes. The operator can hold the upper end of the bar in his bare hand as the current only passes through the lower portion thereof between the eye and the solution. The work is done on different sized pieces without the use of resistances, the piece itself serving to regulate the current. The bar takes off from the line more or less current according to the volume required to effect the heating. The apparatus being capable of supplying sufficient current to heat the larger pieces required to be heated, when such a piece is placed in circuit with the bath it will take a maximum current. When a smaller piece is placed in circuit, the quantity of the current passing over the line is reduced. The current is thus regulated by the size of the piece and a rheostat or other means of regulation is dispensed with.

Ido not confine myself to this particular form of automatic clamp as any mechanical equivalent will effect the same purpose.

I claim as my invention 1. The combination of abath,an automatic clamp for receiving a bar to be heated in said bath, and conductors for connecting said bath and metal holding device with opposite electric poles.

2. The combination of a tank, a bath composed of a suitable liquid disposed in said tank, an automatic clamp mounted on the edge of said tank, and means for connecting said bath and clamp with opposite electric poles.

3. The combination of a receptacle for containin g a resistance bath, an automatic clamp mounted on the edge of said receptacle, the movable jaw of said clamp being provided with means for regulating its action, and conductors connecting said solution and clamp with opposite electric poles.

4. The combination of a receptacle, a bath composed of a suitable liquid disposed in said receptacle, an automatic clamp mounted on said receptacle, the stationary member of which is provided with an eye flared at its upper outer edge and at its lower inner edge, which permits the bar to be adjusted at any desired incline, and conductors connecting said solution and clamp with opposite electric poles.

5. The combination of a receptacle for containing a resistance bath, an automatic clamp mounted thereon and comprising a stationary member provided with an eye flared at its upper outer edge and also at its lower inner edge, and a weighted pin sliding in said eye, and conductors connecting said solution and clamp with opposite electric poles.

GEO. D. BURTON.

Witnesses:

OOIAN P. ADAMS, WALTER L. HAYDEN. 

